Compositions and methods for the maintenance of oral health

ABSTRACT

The invention provides compositions comprising one or more isolated LDH-deficient  mutans streptococcus  strains and one or more isolated  S. oralis  strains and/or one or more isolated  S. uberis  strains. Compositions of the invention are useful to maintain oral health, by for example treating and/or preventing one or more symptoms of dental caries, periodontitis and/or other oral cavity diseases or wounds.

PRIORITY

This application is a continuation application of U.S. Ser. No. 14/518,226, filed Oct. 20, 2014, which is a continuation application of U.S. Ser. No. 13/017,214, filed Jan. 31, 2011, now U.S. Pat. No. 8,865,156, which is a divisional application of U.S. Ser. No. 10/567,592, filed Jun. 30, 2006, now U.S. Pat. No. 7,931,892, which is a U.S. National Phase filing of PCT/US04/025899, filed on Aug. 10, 2004, which claims the benefit of U.S. Provisional patent application Ser. No. 60/494,169, filed Aug. 11, 2003, all of which are incorporated herein in their entirety by reference.

BACKGROUND OF THE INVENTION

Dental caries is characterized by dissolution of the mineral portion of the tooth, which can result in pain and loss of viability of the tooth, necessitating costly repair or extraction of the tooth. Dental caries affects 50% of children aged 5-9 years, 67% of adolescents age 12-17 years, and 94% of adults aged ≥18 years in the US (Morbidity and Mortality Weekly Reports 51: 144-147, 2002). Clean teeth will not decay; however, even with vigorous cleaning it is difficult to keep teeth sufficiently clean. Various methods have been developed to prevent or alleviate dental caries including, for example, the addition of sodium fluoride, sodium silicofluoride or hydrofluosilicic acid to drinking water, and sodium fluoride or tin fluoride to topical preparations, including dentifrices and mouthrinses. The prevention of caries by coating teeth with polymeric materials or sealants has been used; however, these techniques are costly, can require etching of the teeth with phosphoric acid and can be effective only in young children who have not yet developed caries. Antibacterial agents, including antibiotics, have also been proposed as a treatment for dental caries. Antibiotics kill microorganisms that are responsible for producing acid in the mouth such as Streptococcus mutans, but antibiotics are not selective in the killing of oral bacteria and also kill beneficial bacteria present in the oral cavity. This can result in a microbial imbalance in the mouth, which can have serious consequences. Therefore, more effective methods for the treatment and prevention of dental caries are needed in the art.

Actinobacillus actinomycetemcomitans (Aa) is the principal etiologic agent of early-onset periodontitis including localized and generalized prepubertal periodontitis, localized and generalized juvenile periodontitis, and rapidly progressive or refractory adult periodontitis. Tooth loss is the ultimate detrimental effect of destructive periodontal disease. A national survey of the United States revealed a prevalence of localized juvenile periodontitis of 0.53% and of generalized juvenile periodontitis of 0.13%. Loe & Brown, J. Periodontol. 62:608-616 (1991). Findings from a number of studies corroborate the conclusion that early-onset disease is similar in other industrialized countries and is more frequent in developing countries. Loe & Brown, J. Periodontol. 62:608-616 (1991).

In addition, certain types of adult periodontitis, which in general are very common conditions affecting over half the adult population, are likely to be caused by a select group of microorganisms indigenous to the oral cavity. These include Aa, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, Treponema denticola, Campylobacter rectus and Eikenella corrodens. There are antibiotic, surgical, and mechanical therapies for the treatment of the various types of periodontitis, but no means for prevention. Tetracycline has been widely used in the treatment of early-onset periodontitis. There remains a concern, however, of strains developing resistance to tetracycline as well as the possibility of overgrowth of other pathogenic microorganisms. Given the incidence of periodontal diseases, safe preventative and treatment strategies are needed in the art. Control of periodontal disease is also very important in light of recent attention to the possible role of periodontal infections as risk factors for systemic disease (e.g., coronary heart disease). Therefore, methods of treatment and prevention of early-onset periodontitis, localized and generalized juvenile periodontitis, and rapidly progressive or refractory adult periodontitis are needed in the art.

BRIEF SUMMARY OF THE INVENTION

The instant invention provides methods and compositions for the maintenance of oral health, such as the treatment and/or prevention of periodontitis, dental caries, Candida or fungal overgrowth in an oral cavity, halitosis, xerostomia-induced dental caries, oral bacterial infections or diseases, and oral wounds. In one embodiment the invention provides probiotics for the maintenance of oral health.

Probiotics are viable single or mixed culture microorganisms, which when applied to animals or humans, beneficially affect their host by improving the properties of the indigenous microflora. Traditionally, probiotic use has focused on the general category of gastrointestinal health, but the approach of using beneficial organisms has been suggested to prevent or treat other conditions, including application to maintain vaginal and urinary tract health. In the instant invention probiotics are used to maintain oral health.

One embodiment of the invention provides a composition comprising one or more isolated Streptococcus oralis strains and/or one or more S. uberis strains combined with one or more isolated mutans streptococcus strains that are lactate dehydrogenase-deficient. The mutans streptococcus strains can be one or more LDH-deficient strains of S. rattus, S. cricetus, S. mutans, S. sobrinus, S. downeii, S. macacae, and S. ferus. The composition can further comprise a carrier. The mutans streptococcus strain can be a naturally-occurring strain or a genetically modified strain that is lactate dehydrogenase-deficient. A mutans streptococcus strain can be, for example, a S. rattus strain JH145. A S. oralis strain can be, for example, S. oralis strain KJ3 or KJ3sm. A S. uberis strain can be, for example, KJ2 or KJ2 sm.

Another embodiment of the invention provides a food composition comprising one or more isolated S. oralis strains and/or one or more isolated S. uberis strains, and one or more isolated mutans streptococcus strains, wherein the mutans streptococcus strains are lactate dehydrogenase-deficient.

Still another embodiment of the invention provides a dentifrice, chewing gum, lozenge, oral rinse, or topical agent composition comprising one or more isolated S. oralis strains and/or one or more isolated S. uberis strains, and one or more isolated mutans streptococcus strains, wherein the mutans streptococcus strains are lactate dehydrogenase-deficient.

Yet another embodiment of the invention provides a method for maintaining oral health of a subject comprising administering to an oral cavity of a subject a composition comprising one or more isolated S. oralis strains and/or one or more isolated S. uberis strains and one or more isolated mutans streptococcus strains, wherein the mutans streptococcus strains are lactate dehydrogenase-deficient. The composition can be administered to the subject about once a day, about once a week or about once a month. The subject can be a mammal, such as a human. Maintaining oral health can comprise the treatment, prevention, or both treatment and prevention of periodontitis, dental caries, Candida or fungal overgrowth, halitosis, xerostomia-induced dental caries or periodontitis, oral bacterial infections or diseases, oral wounds or a combination thereof.

Even another embodiment of the invention provides a method of non-persistently colonizing an oral cavity of a subject with therapeutically-effective bacteria comprising administering to the oral cavity of a subject a combination comprising one or more isolated S. oralis strains and/or one or more isolated S. uberis strains, and one or more isolated mutans streptococcus strains, wherein the mutans streptococcus strains are lactate dehydrogenase-deficient. The subject can be a mammal, such as a human.

Therefore, the invention provides methods and compositions for the maintenance of oral health, including, for example, the prevention and/or treatment of dental caries, periodontitis, Candida or fungal overgrowth, halitosis, or xerostomia-induced dental caries or periodontal disease oral bacterial infections or diseases, oral wounds or a combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the results of administration of daily treatment with JH145.

FIGS. 2A-C show the comparison of a S. mutans JH145 ldh gene to a S. mutans BHT-2 ldhgene and the corresponding protein sequences.

DETAILED DESCRIPTION OF THE INVENTION

Probiotics can be defined as the administration of live microorganisms in adequate amounts to confer a health benefit on the host. Though originally developed for “gut health”, probiotics are now being investigated in immune system modulation, vaginal and urinary tract health, allergies, inflammatory disorders and hypertension. Bacteria are normal inhabitants of humans, and the oral cavity provides an ecological niche for over 300 microbial species. Microbial interactions are logically of enormous importance in controlling the ecology of dental plaque and, thus, the outcome: oral health or disease. One preventive approach is to encourage colonization and growth of protective species or the establishment of a microbial flora that is balanced in favor of health. Beneficial effects can involve the production of a specific enzyme(s) or metabolite(s), or the probiotic organism can also cause the body to produce the beneficial action. A beneficial effect can also be achieved by inhibition of colonization or outgrowth of a pathogenic microorganism by competition for nutrients or attachment sites.

The invention provides compositions, therapeutic systems and methods of use for the maintenance of oral health including, for example, the treatment and/or prevention of dental caries, periodontitis, oral bacterial infections and diseases, oral wounds, Candida or fungal overgrowth, halitosis, or xerostomia-induced dental caries or periodontal disease, the promotion of wound healing, or a combination thereof in a subject. A composition of the invention comprises a therapeutically effective amount of one or more isolated strains of LDH-deficient mutans streptococcus in combination with a therapeutically effective amount of one or more isolated strains of S. oralis and/or one or more isolated strains of S. uberis.

Streptococcus oralis and Streptococcus uberis

Streptococcus oralis (previously known as S. sanguis Type II) and S. uberis are important components in maintaining the normal, healthy balance of microorganisms that compose the periodontal flora. See, Socransky et al., Oral Microbiol. Immunol. 3:1-7 (1988); Hillman and Shivers, Arch. Oral. Biol., 33:395-401 (1988); Hillman, et al., Arch. Oral. Biol., 30:791-795 (1985). S. oralis produces hydrogen peroxide, which can inhibit periodontal pathogens such as Actinobacillus actinomycetemcomitans (Aa), Bacteroides forsythus, and P. intermedia. Therefore, S. oralis and S. uberis can be useful in the maintenance of oral health. Compositions of the invention comprise one or more isolated strains of S. oralis, for example, ATCC 35037, ATCC 55229, ATCC 700233, ATCC 700234 and ATCC 9811. Other strains of S. oralis include KJ3 and KJ3sm. KJ3sm is a naturally occurring genetic variant of KJ3 that is resistant to streptomycin. The streptomycin resistance is advantageous because it provides a marker for easy isolation of the bacteria. Additionally, streptomycin resistant strains are slightly attenuated and do not survive as long in an oral cavity as wild-type strains. This property is useful where the goal is to non-persistently colonize the oral cavity of an animal with the bacteria.

S. uberis in plaque has been found to correlate with periodontal health, in particular by interfering with the colonization by periodontal pathogens such as Porphyromonas gingivalis, Campylocbacter recta, and Eikenella corrodens. Compositions of the invention can comprise one or more isolated strains of S. uberis, for example, ATCC 13386, ATCC 13387, ATCC 19435, ATCC 27958, ATCC 35648, ATCC 700407, ATCC 9927, strain KJ2 or strain KJ2sm. KJ2sm is a naturally occurring genetic variant of KJ2. That is streptomycin resistant and provides the same advantages as for streptomycin-resistant strains of S. oralis. One or more isolated strains of S. oralis or one or more isolated strains of S. uberis, or both, can be used in compositions and methods of the invention.

Mutans Streptococcus

Compositions of the invention comprise one or more isolated mutans streptococcus bacteria species deficient in the production of lactic acid. These strains include, for example, S. rattus, S. cricetus, S. mutans, S. sobrinus, S. downeii, S. macacae, and S. ferus. A mutans streptococcus strain of the invention does not substantially produce L(+) lactate dehydrogenase (LDH). Such a strain is termed an LDH-deficient strain. An LDH-deficient strain of mutans streptococcus produces 75%, 80%, 90%, 95%, 98%, 99%, or 100% less lactic acid than wild-type strains of mutans streptococcus. An LDH-deficient mutans streptococcus strain can be a naturally occurring strain of mutans streptococcus or a genetically modified strain of mutans streptococcus. LDH-deficient mutans streptococcus can compete with and/or displace pathogenic bacteria such as S. mutans, a principal etiological agent of dental caries, in the oral cavity. LDH-deficient mutans streptococcus stains will compete with S. mutans for the same nutrients, colonization sites, etc. in an oral cavity when administered as a probiotic. Therefore, LDH-deficient mutans streptococcus strains can be used to, for example, prevent and/or treat dental caries. LDH-deficient strains of mutans streptococcus are non-pathogenic, alter the microenvironment of the oral cavity to prevent colonization or outgrowth of pathogenic organisms, and/or displace pathogenic organisms from the oral cavity where the pathogen is part of the host's indigenous flora.

Examples of LDH-deficient mutans streptococcus strains include, for example, S. rattus JH145 (ATCC 31377) (a spontaneous, naturally-occurring LDH-deficient mutant) (See FIGS. 2A-C for a JH145 mutant LDH nucleotide and polypeptide sequence) and JH140 (ATCC 31341) (a chemically-modified LDH-deficient mutant). See e.g., Stanshenko & Hillman, Microflora of plaque in rats following infection with an LDH-deficient mutant of Streptococcus rattus, Caries Res. 23:375-377 (1989); Hillman, Lactate dehydrogenase mutants of Streptococcus mutans: Isolation and preliminary characterization. Infect. Immun. 21:206-212 (1978); see also Abhyankar et al., Serotype c Streptococcus mutans mutatable to lactate dehydrogenase deficiency. J Dent Res 1985 November; 64(11):1267-71.

An LDH-deficient strain of mutans streptococcus can be derived from a mutans streptococcus strain using, for example, chemical or physical mutagenesis techniques. Strains that are mutagenized using these techniques are considered genetically modified strains. For example, a mutans streptococcus strain can be subjected to mutagens such as nitrous acid, formic acid, sodium bisulphate, UV light, base analog mutagens, including for example, 5-bromo-deoxyuridine (5BU), alkylators such as ethyl methane sulfonate (EMS), methyl methane sulfonate (MMS), diethylsulfate (DES), and nitrosoguanidine (NTG, NG, MNNG). See e.g., In Vitro Mutagenesis Protocols, Braman, Ed., Humana Press, 2002.

Naturally-occurring, spontaneous LDH-deficient mutans streptococcus strains can be prepared using methods disclosed in, for example, Hillman, Lactate dehydrogenase mutants of Streptococcus mutans: isolation and preliminary characterization. Infect. Immun. 21:206-212 (1978). Spontaneous LDH-deficient mutants occur at the rate of approximately 10⁻⁵ frequency. See Johnson et al., Cariogenic potential in vitro in man and in vivo in the rat of lactate dehydrogenase mutants of Streptococcus mutans. Arch. Oral Biol. 25:707-713 (1980).

Naturally-occurring, spontaneous LDH-deficient strains of mutans streptococcus can be differentiated from LDH-producing strains of mutans streptococcus by plating the bacteria on glucose tetrazolium medium. LDH-deficient mutans streptococcus colonies will be bright red and relatively larger in size than colonies of the parent strain, which are white and relatively smaller in size on the glucose tetrazolium medium. Naturally-occurring, spontaneous LDH-deficient strains of mutans streptococcus can be used in a composition of the invention.

An LDH-deficient strain of S. rattus has been isolated. Briefly, a culture of S. rattus BHT-2 was grown overnight to saturation in Todd Hewitt broth, and diluted samples were spread on glucose tetrazolium medium to give approximately 300 colonies per plate. Wild-type, acid producing colonies are white on this medium. LDH-deficient mutants are bright red. S. rattus JH145 was one red colony amid approximately 100,000 white colonies that were screened. S. rattus JH145 is therefore a naturally-occurring, LDH-deficient mutant.

LDH-deficient strains of mutans streptococcus, such as LDH-deficient mutants of S. rattus BHT-2, produce less total titratable acid when incubated in the presence of glucose and other sugars or polyols, make substantially less lactic acid when incubated in the presence of glucose in the case of resting and growing cultures, adhere better to hydroxyapitite and accumulate more plaque when grown in the presence of sucrose. LDH activity can be assayed as described by Brown & Wittenberger (J. Bacteriol. 110:604, 1972).

Terminal pH can be determined by subculturing strains (1:100) in Todd-Hewitt broth containing 1% glucose. After 48 hours incubation in candle jars at 37° C., the absorbance at 580 nm and pH of the cultures can be determined. Lactic acid concentration of cultures can be determined by gas-liquid chromatography. See Salanitro & Muirhead, Quantitative method for the gas chromatographic analysis of short-chain monocarboxylic and dicarboxylic acids in fermentation media. Appl. Microbiol. 29:374-381 (1975); Hillman et al., Acetoin production by wild-type strains and a lactate dehydrogenase-deficient mutant of Streptococcus mutans. Infect. Immun. 55:1399-1402 (1987).

Additionally, any genetic modification techniques known to those of skill in the art can be used to create an LDH-deficient mutans streptococcus strain from an LDH-producing mutans streptococcus parent strain. For example, an LDH gene or a portion of an LDH gene can be deleted or mutagenized, including, for example, insertional mutagenesis techniques. Other mutagenesis techniques include, for example, homologous recombination, recursive sequence recombination, oligonucleotide-directed mutagenesis, site-directed mutagenesis, error-prone PCR, phosphothioate-modified DNA mutagenesis, uracil-containing template mutagenesis, gapped duplex mutagenesis, point mismatch repair mutagenesis, repair-deficient host strain mutagenesis, radiogenic mutagenesis, deletion mutagenesis, restriction-selection mutagenesis, restriction-purification mutagenesis, site saturation mutagenesis, ensemble mutagenesis, recursive ensemble mutagenesis, and chimeric nucleic acid creation. Therefore, any genetic modification technique that disables an LDH gene can be used to produce an LDH-deficient mutans streptococcus strain.

In one embodiment of the invention, the LDH-deficient strains, whether naturally-occurring or genetically-modified mutants, have a reversion frequency less than 10⁻⁷ and produce less than 10% of the parental level of lactate dehydrogenase activity.

Compositions of the Invention

Compositions of the invention comprise one or more isolated strains of mutans streptococcus combined with one or more isolated strains of S. oralis, or one or more isolated strains of S. uberis, or both one or more isolated strains of S. oralis and one or more isolated strains of S. uberis, wherein the mutans streptococcus strain is lactate dehydrogenase (LDH)-deficient. The combination of LDH-deficient mutans streptococcus with S. oralis and/or S. uberis provides a significant practical advantage in that the combination can used to prevent and treat, for example, both dental caries and periodontitis. Treatment of dental caries and/or periodontitis means that one or more symptoms of dental caries and/or periodontitis is alleviated, reduced, prevented or ameliorated either permanently or temporarily. Compositions and methods of the invention can also be used to treat or prevent Candida or fungal overgrowth in an oral cavity, due to, for example, antibiotic treatment, to treat or prevent halitosis (bad breath), and to treat or prevent dental caries and/or periodontitis associated with xerostomia (dry mouth), to treat or prevent oral bacterial infections or diseases, to treat or prevent oral wounds and combinations thereof.

Mutans streptococcus, S. oralis and/or S. uberis strains of the invention can be present in any therapeutically effective ratio. Therapeutically effective means effective to alleviate, reduce, prevent and/or ameliorate one or more symptoms of dental caries, periodontitis, bacterial infections or diseases, oral wounds, Candida or fungal overgrowth, halitosis, or xerostomia-induced dental caries or periodontal disease or a combination thereof either permanently or temporarily. Therapeutically effective also means effective to promote wound healing in an oral cavity.

The bacterial strains of the invention can further comprise a pharmaceutically acceptable or nutritionally acceptable carrier. The carrier is physiologically compatible with the oral cavity of the subject to which it is administered. Carriers can be comprised of solid-based, dry materials for formulation into tablet, capsule, lozenge, or powdered form. A carrier can also be comprised of liquid or gel-based materials for formulations into liquid, gel, and chewing gum forms.

Suitable liquid or gel-based carriers include but are not limited to: water, physiological salt solutions, urea, alcohols and derivatives, and glycols (e.g., ethylene glycol or propylene glycol). Compositions of the invention can also include natural or synthetic flavorings and food-quality coloring agents, all of which are compatible with maintaining viability of the bacterial strains of the invention. Thickening agents can also be added to compositions of the invention such as corn starch, guar gum, carbopol, and xanthan gum.

Flavorings and/or colorants can also be included in the carrier. Compositions of the invention can also include a plasticizer such as glycerol or polyethylene glycol. The composition of the carrier can be varied so long as it does not interfere significantly with the therapeutic activity of the bacterial strains of the invention.

A composition can be formulated to be suitable for oral administration in a variety of ways, for example in a liquid, a dried mass, a dentifrice, a mouth wash, an oral rinse, a liquid suspension, a topical agent, a powdered food supplement, a paste, a gel, a solid food, a packaged food, a wafer, lozenge, chewing gum and the like. Other formulations will be readily apparent to one skilled in the art. A composition of the invention can include a nutrient supplement component and can include any of a variety of nutritional agents, as are well known, including vitamins, minerals, essential and non-essential amino acids, carbohydrates, lipids, foodstuffs, dietary supplements, and the like.

Bacteria of the invention can be prepared in, for example, a fermenter. The bacteria can be harvested from the fermenter and can be, for example, concentrated. Bacteria of the invention can be prepared for use by, for example, dehydration or spray drying. Spray drying generally comprises spraying a suspension of bacteria in a vessel and under a steam of hot air. Bacteria can also be prepared for use by microencapsulation (see e.g., U.S. Pat. No. 6,251,478), freeze-drying, or by coating with a protective substance such as, for example, lipid material such as triacylglycerols, waxes, organic esters, soybean oil, cottonseed oil, palm kernel oil, and esters of long-chain fatty acids and alcohols.

Methods of Maintaining Oral Health

Pathogenic bacteria, such as S. mutans and Actinobacillus actinomycetemcomitans, which can colonize an oral cavity of an animal, can be inhibited and/or controlled by administering a composition comprising one or more LDH-deficient mutans streptococcus strains and one or more isolated S. oralis strains, or one or more isolated S. uberis strains, or both one or more isolated S. oralis strains and one or more isolated S. uberis strains to an oral cavity. Compositions can be administered to an oral cavity of a subject such as an animal, including a mammal, for example, a human, a non-human primate, a dog, a cat, a rat, a mouse, a horse, a goat, or a rabbit. The bacterial strains of the invention can form at least a part of the transient or indigenous flora of an oral cavity and exhibit beneficial prophylactic and/or therapeutic effects in the cavity.

The invention provides methods for the treatment, prevention, or both treatment and prevention of dental carries, periodontitis, Candida or fungal overgrowth, halitosis, or xerostomia-induced dental caries or periodontal disease oral bacterial infections or diseases, oral wounds or a combination thereof comprising administering a composition of the invention to an oral cavity of a subject. Periodontitis includes, for example, early-onset periodontitis, localized and generalized juvenile periodontitis, and rapidly progressive or refractory adult periodontitis. The composition is administered to the subject about once a day, about once a week or about once a month.

The compositions of the invention can be orally administered in for example, food, water, a dentifrice, a gel, a paste, an emulsion, aerosol spray, chewing gum, lozenge, tablet, capsule, or a liquid suspension. The bacteria can either be already formulated into food, water, gel or other carrier or can be a composition that is added to the carrier by the user prior to consumption.

One embodiment of the invention provides a method of non-persistently colonizing an oral cavity of a subject with therapeutically-effective bacteria comprising administering to the oral cavity of a subject a combination comprising one or more isolated strains of S. oralis and/or S. uberis and one or more isolated strains of mutans streptococcus organisms, wherein the mutans streptococcus organisms are lactate dehydrogenase-deficient. In one embodiment of the invention the administered bacterial strains do not permanently colonize the oral cavity, rather the strains are present in the oral cavity for about 1 day, about 1 week, about 2 weeks, about 3 weeks, about 1 month, about 2 months or about 3 months after administration of the bacteria. Optionally, the bacteria can permanently and persistently colonize the oral cavity of a subject.

Compositions of the invention can be administered at a dose of about 1×10³, 1×10⁵, 1×10⁷, 1×10⁹, or 1×10¹¹ CFU of viable bacteria. One, two, or more doses can be administered per day for about 1 week, about 2 weeks, about 1 month, about 2 months, about 3 months, about a year or more. Alternatively, a dose can be administered about every other day, about once a week, about once a month or about yearly.

Example 1

Mutans streptococci for Maintenance of Oral Health

Daily treatment with JH145 results in decreased levels of indigenous Streptococcus mutans because of competition for nutrients, attachment sites, and other factors. The reduced levels of indigenous S. mutans promotes dental health, since this microorganism is closely associated with dental caries.

Seventy-two weanling (24 day-old) Sprague-Dawley rats were infected with S. mutans strain NG8 by pipetting 100 microliters of a suspension containing approximately 10¹⁰ cells per ml into their mouths using a micropipettor. The infection regimen was repeated twice on consecutive days. The animals were maintained on diet TD 80406 (Harlan Teklad) and water ad lib, caged separately. NG8 was allowed to establish itself for 4 weeks. The animals were randomly divided into 6 groups of 12 and treated daily for 16 weeks as follows:

-   -   a. Animals in group 1 received 100 microliters of a suspension         of JH145 containing 10¹⁰ cells per ml using a micropipettor.     -   b. Animals in group 2 received 100 microliters of a suspension         of JH145 containing 10⁹ cells per ml using a micropipettor.     -   c. Animals in group 3 received 100 microliters of a suspension         of JH145 containing 10⁸ cells per ml using a micropipettor.     -   d. Animals in group 4 received 100 microliters of a suspension         of JH145 containing 10⁷ cells per ml using a micropipettor.     -   e. Animals in group 5 received 100 microliters of a suspension         of JH145 containing 10⁶ cells per ml using a micropipettor.     -   f. Animals in group 6 are sham treated.

At weekly intervals, plaque and saliva were sampled using cotton tipped swabs, and samples plated on S. mutans screening/selection medium to selectively cultivate NG8 (white colonies) and JH145 (red colonies). Levels of NG8 were plotted as a function of time. See FIG. 1.

Using a Univariate Analysis of Variance (ANOVA) to examine differences among the six groups (i.e., 5 treatment and 1 control) during week 9, results indicated a significant group effect, F (5, 63)=5.53, p<0.001. The effect size (ES=0.31) and observed power (Φ=0.99) for this analysis indicated that there was a sufficient amount of power to detect this small effect between the groups. Follow up t tests with Bonferroni correction (p=0.01) were conducted using a priori planned comparisons, which tested each treatment group against the control. These analyses indicated that treatment groups 1-4 exhibited significantly less S. mutans NG8 expression relative to the control group, t's (1, 21)≥2.7, p≤0.01.

Therefore, daily treatment of rats with >10⁶ cells of JH145 results in decreased levels of indigenous S. mutans. A decreased risk of dental caries and improved dental health should follow. The effect of the treatment is likely to be significantly better in human subjects who would hold and swish the probiotic in their mouths for 30 to 60 seconds per treatment. Relative to the rat, which quickly swallows the probiotic preparation, the longer exposure of human teeth to JH145 should increase the opportunity for it to compete with indigenous S. mutans, resulting in improved effectiveness.

Human studies can be performed to verify that daily exposure with a suspension of mutans streptococci for example, S. rattus JH145 (ldh,str) results in decreased numbers of an indigenous S. mutans strain and cessation of the exposure results in eventual elimination of S. rattus JH145 and return of the indigenous S. mutans to original levels. Baseline levels of indigenous S. mutans can be determined. Daily doses of S. rattus JH145 can be administered to the oral cavity of the subjects. The oral flora of the subjects can be sampled weekly and wild-type S. mutans and S. rattus JH145 levels monitored until a decrease in wild-type S. mutans levels is observed. S. rattus JH145 doses are discontinued and oral flora is sampled weekly to follow decline in S. rattus JH145 levels and increase in wild-type S. mutans levels

Streptococcus oralis and Streptococcus uberis for Maintenance of Periodontal Health

Human studies can be done to verify that daily exposure with a suspension of S. oralis (str) and/or S. uberis results in decreased numbers of indigenous periodontopathic species and cariogenic species and that cessation of the treatment results in eventual elimination of the S. oralis and/or S. uberis probiotic strain and return of the periodontopathic species and cariogenic species to original levels.

For example, baseline levels of 4 periodontopathic bacteria in saliva can be determined for human subjects. Daily doses of S. oralis and/or S. uberis can be administered to the oral cavity of human subjects. The oral flora of the human subjects can be sampled weekly to monitor pathogen and S. oralis and/or S. uberis levels until a decrease in levels of one or more pathogens is observed. The S. oralis and/or S. uberis doses are stopped and oral flora of the human subjects is sampled weekly to follow the decline in S. oralis and/or S. uberis levels and the corresponding increase in pathogen levels.

Finally, human studies and animal studies can be done to verify that daily exposure with a suspension of one or more isolated S. oralis (str) and/or S. uberis strains in combination with one or more isolated LDH-deficient mutans streptococcus strains results in decreased numbers of indigenous periodontopathic species and that cessation of the treatment results in eventual elimination of the probiotic strains and return of the periodontopathic species to original levels.

All patents, patent applications, and other scientific or technical writings referred to anywhere herein are incorporated by reference in their entirety. The invention illustratively described herein suitably can be practiced in the absence of any element or elements, limitation or limitations that are not specifically disclosed herein. Thus, for example, in each instance herein any of the terms “comprising”, “consisting essentially of”, and “consisting of” may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by embodiments, optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the description and the appended claims.

In addition, where features or aspects of the invention are described in terms of Markush groups or other grouping of alternatives, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group or other group. 

What is claimed is:
 1. A food formulation comprising: a bacterial formulation comprising one or more of a biologically pure mutans streptococci strains selected from the group consisting of Streptococcus rattus, Streptococcus cricetus, Streptococcus mutans, Streptococcus sobrinus, Streptococcus downeii, Streptococcus macacae, and Streptococcus ferus; wherein said mutans streptococcus strains are genetically modified strains that are lactate dehydrogenase-deficient, one or more biologically pure Streptococcus oralis strains, and one or more biologically pure Streptococcus uberis strains; and a carrier comprising a nutritional agent.
 2. The food formulation of claim 1, wherein the bacterial formulation is provided as a discrete composition that is added to the carrier by a user prior to consumption.
 3. The food formulation of claim 1, wherein the food formulation is selected from the group consisting of a powdered food supplement, a paste, a gel, a solid food, a packaged food, a wafer, a lozenge, and a chewing gum.
 4. The food formulation of claim 1, wherein the nutritional agent is selected from the group consisting of a vitamin, a mineral, an amino acid, a carbohydrate, a lipid, and a dietary supplement.
 5. The food formulation of claim 1, further comprising a flavoring.
 6. The food formulation of claim 1, further comprising a food-quality coloring agent.
 7. The food formulation of claim 1, further comprising a thickening agent.
 8. The food formulation of claim 7, wherein the thickening agent is selected from the group consisting of corn starch, guar gum, carbopol, and xanthan gum.
 9. The food formulation of claim 1, further comprising a plasticizer.
 10. The food formulation of claim 9, wherein the plasticizer is glycerol or polyethylene glycol.
 11. The food formulation of claim 1, wherein the food formulation is provided as a consumable portion comprising from 10³ CFU to 10¹¹ CFU of viable bacteria. 